Incorporate slim-lint design back into haml-lint

The `slim-lint` project was created using `haml-lint` as a template, but
then improved on it to make 100% code coverage possible.

Incorporate the changes back into `haml-lint`, since much of the
framework code is identical. This paves the way for us to consider
extracting the framework code into a separate gem.

This includes a bunch of specs so we can get `haml-lint` closer to 100%
code coverage.

config/default.yml

@@ -61,6 +61,7 @@ linters:
       - Style/AlignParameters
       - Style/BlockNesting
       - Style/FileName
+      - Style/FinalNewline
       - Style/IfUnlessModifier
       - Style/IndentationWidth
       - Style/Next

lib/haml_lint.rb

@@ -2,7 +2,7 @@
 require 'haml_lint/exceptions'
 require 'haml_lint/configuration'
 require 'haml_lint/configuration_loader'
-require 'haml_lint/parser'
+require 'haml_lint/document'
 require 'haml_lint/haml_visitor'
 require 'haml_lint/lint'
 require 'haml_lint/linter_registry'
@@ -11,6 +11,7 @@
 require 'haml_lint/logger'
 require 'haml_lint/reporter'
 require 'haml_lint/report'
+require 'haml_lint/linter_selector'
 require 'haml_lint/file_finder'
 require 'haml_lint/runner'
 require 'haml_lint/utils'

lib/haml_lint/cli.rb

@@ -1,12 +1,13 @@
+require 'haml_lint'
 require 'haml_lint/options'
 
 require 'sysexits'
 
 module HamlLint
   # Command line application interface.
   class CLI
-    attr_accessor :options
-
+    # Create a CLI that outputs to the specified logger.
+    #
     # @param logger [HamlLint::Logger]
     def initialize(logger)
       @log = logger
@@ -16,7 +17,7 @@ def initialize(logger)
     # based on those arguments.
     #
     # @param args [Array<String>] command line arguments
-    # @return [Fixnum] exit status returned by the application
+    # @return [Integer] exit status code
     def run(args)
       options = HamlLint::Options.new.parse(args)
       act_on_options(options)
@@ -28,6 +29,9 @@ def run(args)
 
     attr_reader :log
 
+    # Given the provided options, execute the appropriate command.
+    #
+    # @return [Integer] exit status code
     def act_on_options(options)
       log.color_enabled = options.fetch(:color, log.tty?)
 
@@ -48,6 +52,8 @@ def act_on_options(options)
       end
     end
 
+    # Outputs a message and returns an appropriate error code for the specified
+    # exception.
     def handle_exception(ex)
       case ex
       when HamlLint::Exceptions::ConfigurationError
@@ -69,21 +75,27 @@ def handle_exception(ex)
       end
     end
 
+    # Scans the files specified by the given options for lints.
+    #
+    # @return [Integer] exit status code
     def scan_for_lints(options)
       report = Runner.new.run(options)
       print_report(report, options)
       report.failed? ? Sysexits::EX_DATAERR : Sysexits::EX_OK
     end
 
+    # Outputs a report of the linter run using the specified reporter.
     def print_report(report, options)
-      reporter = options.fetch(:reporter, Reporter::DefaultReporter).new(log, report)
-      reporter.report_lints
+      reporter = options.fetch(:reporter,
+                               HamlLint::Reporter::DefaultReporter).new(log)
+      reporter.display_report(report)
     end
 
+    # Outputs a list of all currently available linters.
     def print_available_linters
       log.info 'Available linters:'
 
-      linter_names = LinterRegistry.linters.map do |linter|
+      linter_names = HamlLint::LinterRegistry.linters.map do |linter|
         linter.name.split('::').last
       end
 
@@ -92,10 +104,11 @@ def print_available_linters
       end
     end
 
+    # Outputs a list of currently available reporters.
     def print_available_reporters
       log.info 'Available reporters:'
 
-      reporter_names = Reporter.descendants.map do |reporter|
+      reporter_names = HamlLint::Reporter.descendants.map do |reporter|
         reporter.name.split('::').last.sub(/Reporter$/, '').downcase
       end
 
@@ -104,14 +117,18 @@ def print_available_reporters
       end
     end
 
+    # Outputs help documentation.
     def print_help(options)
       log.log options[:help]
     end
 
+    # Outputs the application name and version.
     def print_version
-      log.log "#{APP_NAME} #{HamlLint::VERSION}"
+      log.log "#{HamlLint::APP_NAME} #{HamlLint::VERSION}"
     end
 
+    # Outputs the backtrace of an exception with instructions on how to report
+    # the issue.
     def print_unexpected_exception(ex)
       log.bold_error ex.message
       log.error ex.backtrace.join("\n")

lib/haml_lint/configuration.rb

@@ -1,6 +1,12 @@
 module HamlLint
-  # Stores configuration for haml-lint.
+  # Stores runtime configuration for the application.
+  #
+  # The purpose of this class is to validate and ensure all configurations
+  # satisfy some basic pre-conditions so other parts of the application don't
+  # have to check the configuration for errors. It should have no knowledge of
+  # how these configuration values are ultimately used.
   class Configuration
+    # Internal hash storing the configuration.
     attr_reader :hash
 
     # Creates a configuration from the given options hash.
@@ -11,6 +17,14 @@ def initialize(options)
       validate
     end
 
+    # Access the configuration as if it were a hash.
+    #
+    # @param key [String]
+    # @return [Array,Hash,Number,String]
+    def [](key)
+      @hash[key]
+    end
+
     # Compares this configuration with another.
     #
     # @param other [HamlLint::Configuration]
@@ -30,19 +44,9 @@ def for_linter(linter)
           linter.name.split('::').last
         when HamlLint::Linter
           linter.name
-        else
-          linter.to_s
         end
 
-      smart_merge(@hash['linters']['ALL'],
-                  @hash['linters'].fetch(linter_name, {})).freeze
-    end
-
-    # Returns whether the specified linter is enabled by this configuration.
-    #
-    # @param linter [HamlLint::Linter,String]
-    def linter_enabled?(linter)
-      for_linter(linter)['enabled'] != false
+      @hash['linters'].fetch(linter_name, {}).dup.freeze
     end
 
     # Merges the given configuration with this one, returning a new
@@ -56,18 +60,14 @@ def merge(config)
 
     private
 
-    # Validates the configuration for any invalid options, normalizing it where
-    # possible.
-    def validate
-      @hash = convert_nils_to_empty_hashes(@hash)
-      ensure_linter_section_exists(@hash)
-    end
-
+    # Merge two hashes such that nested hashes are merged rather than replaced.
+    #
+    # @param parent [Hash]
+    # @param child [Hash]
+    # @return [Hash]
     def smart_merge(parent, child)
       parent.merge(child) do |_key, old, new|
         case old
-        when Array
-          old + Array(new)
         when Hash
           smart_merge(old, new)
         else
@@ -76,21 +76,32 @@ def smart_merge(parent, child)
       end
     end
 
-    def ensure_linter_section_exists(hash)
-      hash['linters'] ||= {}
-      hash['linters']['ALL'] ||= {}
+    # Validates the configuration for any invalid options, normalizing it where
+    # possible.
+    def validate
+      ensure_exclude_option_array_exists
+      ensure_linter_section_exists
+      ensure_linter_include_exclude_arrays_exist
+    end
+
+    # Ensures the `exclude` global option is an array.
+    def ensure_exclude_option_array_exists
+      @hash['exclude'] = Array(@hash['exclude'])
     end
 
-    def convert_nils_to_empty_hashes(hash)
-      hash.each_with_object({}) do |(key, value), h|
-        h[key] =
-          case value
-          when nil  then {}
-          when Hash then convert_nils_to_empty_hashes(value)
-          else
-            value
-          end
-        h
+    # Ensures the `linters` configuration section exists.
+    def ensure_linter_section_exists
+      @hash['linters'] ||= {}
+    end
+
+    # Ensure `include` and `exclude` options for linters are arrays
+    # (since users can specify a single string glob pattern for convenience)
+    def ensure_linter_include_exclude_arrays_exist
+      @hash['linters'].keys.each do |linter_name|
+        %w[include exclude].each do |option|
+          linter_config = @hash['linters'][linter_name]
+          linter_config[option] = Array(linter_config[option])
+        end
       end
     end
   end

lib/haml_lint/configuration_loader.rb

@@ -4,10 +4,12 @@
 module HamlLint
   # Manages configuration file loading.
   class ConfigurationLoader
-    DEFAULT_CONFIG_PATH = File.join(HAML_LINT_HOME, 'config', 'default.yml')
+    DEFAULT_CONFIG_PATH = File.join(HamlLint::HOME, 'config', 'default.yml')
     CONFIG_FILE_NAME = '.haml-lint.yml'
 
     class << self
+      # Load configuration file given the current working directory the
+      # application is running within.
       def load_applicable_config
         directory = File.expand_path(Dir.pwd)
         config_file = possible_config_files(directory).find(&:file?)
@@ -19,33 +21,42 @@ def load_applicable_config
         end
       end
 
+      # Loads the built-in default configuration.
       def default_configuration
         @default_config ||= load_from_file(DEFAULT_CONFIG_PATH)
       end
 
       # Loads a configuration, ensuring it extends the default configuration.
+      #
+      # @param file [String]
+      # @return [HamlLint::Configuration]
       def load_file(file)
         config = load_from_file(file)
 
         default_configuration.merge(config)
-      rescue => error
+      rescue Psych::SyntaxError, Errno::ENOENT => error
         raise HamlLint::Exceptions::ConfigurationError,
               "Unable to load configuration from '#{file}': #{error}",
               error.backtrace
       end
 
+      # Creates a configuration from the specified hash, ensuring it extends the
+      # default configuration.
+      #
+      # @param hash [Hash]
+      # @return [HamlLint::Configuration]
       def load_hash(hash)
         config = HamlLint::Configuration.new(hash)
 
         default_configuration.merge(config)
-      rescue => error
-        raise HamlLint::Exceptions::ConfigurationError,
-              "Unable to load configuration from '#{file}': #{error}",
-              error.backtrace
       end
 
       private
 
+      # Parses and loads a configuration from the given file.
+      #
+      # @param file [String]
+      # @return [HamlLint::Configuration]
       def load_from_file(file)
         hash =
           if yaml = YAML.load_file(file)
@@ -57,6 +68,11 @@ def load_from_file(file)
         HamlLint::Configuration.new(hash)
       end
 
+      # Returns a list of possible configuration files given the context of the
+      # specified directory.
+      #
+      # @param directory [String]
+      # @return [Array<Pathname>]
       def possible_config_files(directory)
         files = Pathname.new(directory)
                         .enum_for(:ascend)

lib/haml_lint/constants.rb

@@ -1,6 +1,6 @@
 # Global application constants.
 module HamlLint
-  HAML_LINT_HOME = File.expand_path(File.join(File.dirname(__FILE__), '..', '..'))
+  HOME = File.expand_path(File.join(File.dirname(__FILE__), '..', '..'))
   APP_NAME = 'haml-lint'
 
   REPO_URL = 'https://github.com/brigade/haml-lint'